Recently, systems are becoming widespread in which, when a user accesses a web site and selects a text or a photograph on a web page, content such as a URL (Uniform Resource Locator) of a web page linked to the text or the photograph is displayed. For example, items are listed on a web catalog used in a web shopping, and when a user selects a code or a photograph of a desired item, an item page (content) with information of the selected item is displayed. In such a system, item codes or photographs are set in clickable areas, and each clickable area is linked to a URL of an item page.
Patent Literature 1 describes a technology for adding link information to a text or a photograph when converting data for generating printed materials, such as magazines and catalogs, into PDF data.